1. Field of the Invention
The present invention relates to the manufacture of roofing felt and in particular relates to an improved looper apparatus.
2. Prior Art
The basic roofing felt is first manufactured on a paper machine in rolls of approximately 5 feet diameter. The felt is then saturated in asphalt and wound into small diameter rolls for distribution to the roofing industry.
To achieve the penetration of asphalt into the felt for roofing, the 5 feet diameter roll is unwound through a series of hot asphalt sprays, into a hot tank of asphalt and then through a series of strike-in rolls for final penetration. From the strike-in, the sheet of felt, is slowed down and hung in loops in a cooling looper until the product is cold enough to be pulled into the high speed winder. The winder will then meter the length, cut and wind the felt into tight 9" diameter rolls ready for market.
After the felt has been impregnated in the saturating section, it is hung in loops in the cooling looper. The looper slows down the product to a slower speed. After several minutes in the looper, each loop in turn, is pulled or snatched out of the looper bars at a very high speed.
To keep the loops hanging squarely in the looper and to prevent loop dancing with subsequent felt damage, a free running gravity trolley presses lightly against the product.
As the prior art looper chain pulls forward and the loop is removed the trolley moves by gravity to the next loop and so forth. So long as the fingers engage a loop, the trolley is pushed back up the slight incline of the side rails on which it rides by the movement of chain loop which carries the loop in the direction of the winder.
The prior art method and apparatus is illustrated in U.S. Pat. No. 1,880,820.
Since there are many operating variations, the normal free running trolley can press too hard against the sheet and cause damage and cracking in the bottom fold as the loop is pulled out. This cracking may not be detected sometimes and will later show up as a breakdown in the roof.
It is an advantage of the present invention that the trolley is controlled and provides a constant and non-excessive pressure against the hanging loops. It is a feature of the present invention that the trolley moves with the engaged loop. These and other advantages and features will become apparent from the following discussion.